[weidbrewer]

Okay, I checked and the permissions on the library itself are still fine. Here is the full text of my error when trying to connect from my laptop:

ERROR: Bad database location: Bad database location u'/media/library'. Will start with  a new, empty calibre library

Traceback (most recent call last):
  File "site-packages/calibre/gui2/main.py", line 245, in initialize_db
  File "site-packages/calibre/db/legacy.py", line 70, in __init__
  File "site-packages/calibre/db/legacy.py", line 44, in create_backend
  File "site-packages/calibre/db/backend.py", line 349, in __init__
  File "site-packages/calibre/utils/filenames.py", line 115, in is_case_sensitive
IOError: [Errno 13] Permission denied: u'/media/library/calibre_test_case_sensitivity.txt'

The two things that stand out are:

1. u'/media/library' is the location of the mount on the laptop - so the problem is definitly with permissions here, not server side, which might be what Kovid meant.
2. I have also confirmed that Calibre opens fine on the Windows partition of this same computer, if that makes any difference
3. the "/calibre_test_case_sensitivity.txt" file is something that seems to be created when I launch the application, and it is created with locked permissions. Even if I chmod it server side, it re-locks when I try Calibre again. Again, not sure if any of this matters.

So, that's where my trouble-shooting has brought me.